Jiangling Motors South Africa - Vehicle rust

My father bought a white JMC Vigus 2017 model double cab bakkie on 22/05/2018. The bakkie was a year old.The bakkie started to rust from the bottom. My father still have 3 years instalments to pay for a rotten bakkie. The rust is getting to the upper body of the bakkie and getting worst by the day. I went to dealer, the dealer referred us to the manufacturer. They said this is a manufacturing fault. I called JMC Johannesburg and spoke to Johan Pretorius the warranty administrator. He listened to my complain and transferred my call to Johan in sales or parts. Why I don't know. I explained to Johan in sales. He said I should speak to Johan in warranty. Johan the warranty administrator, said he will return my call. He never did. After a number of calls, he said I should send photo's and the info of the vehicle, I did so on the 4/12/19. I followed up, Johan he said he's waiting on head office's reply. I called him again on 3/02/20. Johan said he did forward me head office's reply unfortunately it was declined. I went on my emails while on the line with Johan, I told him have'nt received any emails from him. He said he did send the reply before he went on leave. I asked him to kindly resend the email to me. He agreed, but never did. Today on the 6/02/20, I called him he said he cant seem to find the email. I asked him to ask head office's to resend the email. He said , unfortunately it was an internal communication between South Africa and China and attached a copy of the warranty booklet.